Draft-controlling mechanism for steam-boiler furnaces.



PATENTED MAY 3, 1904.

J. B. GBROULD. DRAFT CONTROLLING MECHANISM FOR STEAM BOILER FURNACES.

APPLICATION FILED OUT. 26, 1903.

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YYI'mnssEs Patented May 3, 1904.

PATENT OFFICE.

JOHN E. GEROULD, OF KANSAS CITY, MISSOURI.

DRAFT-CONTROLLING MECHANISM FOR STEAM-BOILER FURNACES.

SPECIFICATION forming part of Letters Patent No. 758,749, dated May 3, 1904. 7 Application filed October 26, 1903. Serial No. 178,582. (No model.)

To all whom it perry concern:

Be it known that I, JOHN E. GERoULD, a citizen of the United States, residing at Kansas City, in the county of Jackson and State of Missouri, have invented certain new and useful Improvements in Draft-Controlling Mechanisms for Steam-Boiler Furnaces, of which the following is a specification.

My invention relates to improvements in draft-controlling mechanisms for steam-boilers.

The object of my invention is to provide a mechanism for controlling the draft in steamboiler furnaces whereby the combustion of the fuel is rendered perfect and the avoidance of much smoke is accomplished.

My invention comprises a member pivoted at one end, longitudinallyhollow on its upper side and disposed with its hollow side next to and lengthwise of the boiler and forming with the boiler an expansible fine for the passage of the heat and products of combustion from the fire-box, suitable means being provided.

by which the said member may be swung toward or from the boiler for the purpose of expanding or contracting the size of the said passage.

Other novel features of construction are hereinafter fully described and claimed.

In the accompanying drawings, which illustrate my invention, Figure l is a view, partly in side elevation and partly in longitudinal vertical section, of a boiler and furnace provided with a draft-controlling mechanism of my invention. In this view the trough-shaped member is shown, partly in side elevation and partly in vertical section, in solid lines in the open position and by dotted' lines in the closed position. Fig. 2 is a vertical sectional view taken on the dotted line a?) of Fig. 1 looking in the direction indicated by the arrow, the crank-arm of the rock-shaft and the operating-rod being shown in elevation. Fig. 3 is a perspective View of the trough-shaped member and rock-shaft looking from above. Fig. at is a top view of the trough-shaped member, the crank-shaft, and parts connected therewith, the crank-shaft and operating-rod being shown in the forward positions in dotted lines.

Similar characters of reference indicate similar parts.

1 indicates a boiler of the ordinary cylindrical horizontal form,having the usual setting 2 and the fire-box 3. The rear wall of the firebox 3 is provided in its upper end with a semicircular-shaped opening in which is fitted a partly-annular cast ring 4, having a recess 5 in its lower side to receive a projection or lug 6, provided on the inner end and lower side of a trough-shaped member7. The member-7 comprises in its preferable form a body in the form of a longitudinal section of the envelop of the frustum of a cone, the larger end of which is fitted to the inner periphery of the casting 4 and the hollow or concave side of which is disposed next to and lengthwise of the boiler on the under side of the boiler. The sides of the member 7 are adapted when moved to the position shown in Fig. 1 in dotted lines to embrace the sides of the boiler, and with the boiler the member 7 forms a passage for the heat and products of combustion from the fire-box. By swinging the free or outer end of the member 7 upward and downward the size of the draftpassage may be varied. The size and disposition of the rear end of the member 7 are such that a space is always provided between the boiler and the upper side of the member 7, and adjustment of the size of the passage between them is attained by raising the free end of the member 7, thus contracting the space between the said member and the boiler. The lower side of the member 7 is supported by a transverse horizontal rock-shaft 8, the ends of which are pivoted in suitable holes or bearings provided in the side walls of the boiler-setting 9.. From one side of the rock-shaft 8 extends a projection or cam 9, which when the rock-shaft is properly rocked may be forced against the under side of the member 7 and cause the said member to be swung from the position shown in solid lines in Fig. 1 to the position shown in dotted lines in said figure.

the setting 2 one end of the rock-shaft 8 is provided with a crank-arm 10, to which is pivoted one end of a forwardlyextending horizontal operating-rod 11, the forward end of which is slidably mounted in an eye 12,

Outside secured in the boiler-setting. The rear end of the member 7 may be provided with a recess or notch 13, which when the member 7 is in the position shown in dotted lines in Fig. 1 provides a small opening through which products of combustion may escape from the fire-box.

In operating my invention, when it is desired to have a free and unobstructed draft the member 7 is positioned as shown in solid lines in Fig. 1, in which position the member 7 rests upon the rock-shaft 8. If it is desired to restrict the draft and bring the products of combustion directly against the under side of the boiler, the operating-rod 11 is pulled forward, thus rocking the rock-shaft 8 through the intermediacy of the crank-arm 10 and causing the cam or projection 9 to move upwardly and force the member 7 upwardly. When the rock-shaft has been rocked so as to .place the member 7 in the closed position, the

projection or cam 9ris preferably disposed a little forward of the vertical position, the weight of the member 7 then looking the rockshaft against retraction until the operatingvrod is forced rearwardly. If it is desired to retain the member 7 in any position intermediate the fully-closed and the wide-open positions, any suitable. means may be employed for securing the rod 11 against lengthwise movement.

The heat and products of combustion of a gaseous nature passing from the fire-box 3 through the opening in the rear thereof are conducted by the trough like member 7 against the under side of the boiler for a considerable distance along its length, after which they pass through the hollow interior of the setting 2 to the rear end of the boiler, through which they pass by the ordinary tubes 1 L of the boiler to the smoke-stack 15 at the for-' ward end of the boiler. By suitably swinging the member 7 vertically the draft can be readily controlled.

IVIy invention may be modified in many ways without departing from its spirit.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is r 1. In a draft-controlling mechanism for steam-boilers,the combination with the boiler, of the fire-box the upper end of one side of which is provided with a discharge-opening provided in its lower side with a recess, of a trough-shaped flue member provided with a projection on its under side mounted in said recess, the pivoted end of said member being fitted to said opening in the fire-box, the hollow side of said member being disposed next to and lengthwise of the boiler and forming with the boiler a passage for heat and the products of combustion from the fire-box, and means for swinging the free end of said member toward and from the boiler for contracting or expanding the said passage.

2. The combination with the boiler, of the fire-box the upper end of one side of whichis provided with an opening, having in its lower side a recess, a trough-shaped flue member having a projection on its lower side pivoted in the said recess, the rear end of the troughshaped member being fitted to the opening in the wall of the fire-box and embracing the sides of the boiler, a rocking shaft having a cam for raising the trough-shaped member, and means for rocking said shaft.

In testimony whereof I afiiX my signature in presence of two witnesses.

JOHN E. GEROULD.

Witnesses:

WARREN D. HoUsE, B. J. WATERS. 

